telecom • networking • design

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LTE Physical Layer Introductory Videos

Learn about the LTE physical layer from the video series from IEEE and Ericsson. Th video series covers:

  1. LTE protocol structure and architecture
  2. Downlink frame structure, reference signal and MIMO
  3. Downlink control signaling
  4. Uplink SC-FDMA, reference signals and control signaling
  5. TDD and half duplex FDD
  6. Transmission procedures
  7. Cell search, SI and random access procedures

LTE multi antenna transmission


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OFDM and SC-FDMA lectures

OFDM and SC-FDMA video lectures cover OFDM and SC-FDMA is great detail. The following topics are covered:

  • OFDM and multi-carrier modulation
  • Converting a frequency selective channel to a flat fading channel
  • IFFT based multi-carrier modulator bank
  • FFT based multi-carrier demodulator bank
  • Cyclic prefix and circular convolution
  • MIMO OFDM
  • PAPR in OFDM
  • SC-FDMA reduces PAPR

OFDM transmitter schematic

OFDM receiver schematic

Click here to view the OFDM and SC-FDMA lectures


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Long Term Evolution (LTE) Tutorials

Here are a few hand picked links to LTE tutorials. Click here for the complete list.

LTE video tutorial

LTE video presentations

LTE physical layer

OFDM and SC-FDMA Signal Chains

LTE link layer design

data flow through PDCP, RLC, MAC and PHY layers of LTE

This article describes the LTE link-layer protocols, which abstract the physical layer and adapt its characteristics to match the requirements of higher layer protocols.The LTE link-layer protocols are optimized for low delay and low overhead and are simpler than their counterparts in UTRAN. The state -of-the-art LTE protocol design is the result of a careful crosslayer approach where the protocols interact with each other efficiently. This article provides a thorough overview of this protocol stack, including the sub-layers and corresponding interactions in between them, in a manner that is more intuitive than in the respective 3GPP specifications.

Introduction to LTE Architecture


This article provides an overview of the LTE radio interface, together with a more in-depth description of its features such as spectrum flexibility, multi-antenna transmission, and inter-cell interference control. The performance of LTE and some of its key features is illustrated with simulation results.

This article provides a high-level overview of LTE and some of its key components: spectrum flexibility, multi-antenna transmission, and ICIC. Numerical simulations are used to show the performance of the first release of LTE, as well as assess the benefit of the key features. Indeed these contribute strongly to LTE meeting its performance targets. An outlook of the evolution of LTE toward LTE-Advanced and full IMT-Advanced capabilities complete the article. Clearly, LTE offers highly competitive performance and provides a good foundation for further evolution.

LTE Protocol Stack

Click here for a more LTE tutorials that cover the entire spectrum of LTE development.


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LTE Video Presentations

OFDM Time Frequency Multiplexing

Rohde & Schwarz‘s presentations provide an excellent introduction to LTE. The presentations are accompanied with an audio narration. The topics covered are covered:

  1. LTE Introduction
    • Motivations for LTE
    • LTE market and background
    • Requirements
    • Evolution path to LTE
  2. LTE Parameters and Downlink Modulation
    • LTE parameters and frequency bands
    • What is OFDMA?
    • OFDMA multiple access and downlink frame structure
    • OFDMA transmit and receive chains
  3. OFDMA and Downlink Frame Structure Details
    • Downlink OFDMA time-frequency multiplexing
    • LTE Spectrum Flexibility and Bandwidth
    • FDD downlink frame structure detailed
    • TDD frame structure
  4. SC-FDMA and LTE Uplink
    • Introduction to SC-FDMA and uplink frame structure
      • Marriage of single carrier transmission and FDMA
    • Uplink SC-FDMA tranmsit and receive chains
    • Peak to Average Power Ratio (PAPR) comparison with SC-FDMA and OFDMA
  5. Network and Protocol Architecture
    • LTE/SAE network architecture
    • EPC -Evolved Packet Core
    • Base Station control plane and user plane protocol stacks
    • EPC protocol stacks
  6. Channel Mapping and UE Categories
    • Logical and transport channel mapping in downlink and uplink
    • LTE UE Categories
  7. Initial Cell Search and Cell Selection
    • Downlink physical channels and signals
    • Cell Search and Selection in LTE
      • Primary synchronization signal
      • Secondary synchronization signal
      • Reference signals
  8. System Information
    • Downlink reference signal details
    • Master Information Block on PBCH
    • System Information on DL-SCH
  9. Random Access Procedures and EPS Bearer Setup
    • Random access preamble transmission to eNodeB
    • Random access response from eNodeB
    • Resource allocation and contention resolution
    • Signaling on PDCCH
    • Hybrid ARQ
    • RRC Connection Setup and EPS Bearer Setup
  10. Uplink Channels and Signals
    • Uplink physical channels and signals
    • PU-SCH: Physical Uplink Shared Channel
    • Uplink assignment signaling on PDCCH
    • Uplink frequency hopping
    • PUCCH
  11. LTE Mobility and MIMO Introduction
    • Intra MME Handover over the X2 interface
    • RRC States
    • MIMO Basics
      • Transmit diversity
      • Spatial multiplexing
      • Beamforming
  12. Downlink and Uplink MIMO in LTE
    • Downlink MIMO modes
      • Transmit diversity
      • Spatial multiplexing
      • Cyclic delay diversity
      • Beam forming
    • Spatial multiplexing downlink transmitter chain
      • Code book based precoding
    • Uplink MIMO
      • Uplink transmit antenna selection
      • Multi-user MIMO
  13. eNodeB and UE Performance Requirements
    • eNodeB modulation quality measurements
    • eNodeB performance requirements
    • UE performance requirements
  14. UE Certification and Field Trials
    • LTE terminal testing stages
    • LTE terminal certification
    • LTE field trial scenarios


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LTE and WiMax Tutorial

Detailed presentation that covers the following topics:

  • Fundamental constraints from the Shannon Limit
  • Multipath radio propagation
  • Time varying multi-path channel
  • Cellular systems and frequency reuse
  • 4G enabling technologies
    • OFDM/OFDMA
    • SC-FDMA
    • MIMO
    • Fast channel-dependent scheduling
    • Fractional frequency reuse
  • OFDM
    • Orthogonal sub-carriers
    • OFDM implementation using DFT
    • Cyclic Prefix
    • Frequency Domain Equalization
  • SC-FDMA
    • Subcarrier mapping
    • SC-FDMA is DFT precoded OFDMA
    • PAPR characteristics
  • MIMO
    • Spatial diversity
    • Spatial multiplexing
  • Channel dependent scheduling
    • Select channels based on users signal quality in the resource grid
  • LTE specifications
    • Network architecture
    • Frame structure
    • Resource grid
    • Bandwidth configuration
  • LTE physical channels
  • LTE transport channels
  • LTE logical channels
  • Downlink physical channel processing
  • Uplink physical channel processing
  • Random access
  • LTE Advanced
    • Channel aggregation
    • Enhanced MIMO
  • WiMax